Parting and slotting tool



May 8, 1956 Filed Feb. 28, 1952 L. E. LEE

PARTING AND SLOTTING TOOL 3 Sheets-Sheet 1 INVENTOR LUTHER E. LEE

f/ZQQM QBWW ATTORNEYS May 8, 1956 5, LEE 2,744,451

PARTING AND SLOTTING TOOL Filed Feb. 28, 1952 3 Sheets-Sheet 2 FIG. 2

' 4s 45 42 40 y. I 5/ Fla 4 INVENTOR LUTHER E. LEE

JZAQQQM (Q13 WW ATTORNEYS M y 1956 L. E. LEE

PARTING AND SLOTTING TOOL Filed Feb. 28, 1952 INVENTOR LUTHER E. LEEM693; S /2 4am ATTORNEYS PARTING AND SLOTTING TOOL Luther E. Lee, TakomaPark, Md. Application February 28, 1952, Serial No. 274,040

Claims. (Cl. 90-33) (Granted under Title 35, U. S. Code (1952), sec.266) The invention described herein may be manufactured and used byorfor the Government of the United States of America for governmentalpurposes without the payment of royalties thereon or therefor.

This invention relates to cutting tools and more particularly to aparting and slotting tool for finishing a material to close tolerancesin a single operation.

In the past when cutting large billets of metal from the common stock ithas been found necessary to perform a number of finishing operationsupon the billet after initially separating it from the stock in order toreduce the dimensions of the billet to predetermined tolerances. Thesefinishing operations were made necessary by the practice of allowing asmuch as .25 inch in the dimensions for error resulting from crooked orleaning cuts made by tools of the prior art in the initial slottingoperation. The crooked or leaning cuts developed after the tool cutterbit had penetrated a surface of the stock and were usually caused on areturn stroke by the cutter bit contacting the side walls of the groovebeing out which contact caused one edge of the cutter bit to wear fasterthan the other; or by chips which remain in the groove after a cuttingstroke which caused the tool to jump on a return stroke and thus gougeor score the side walls of the groove. The dulling of the cutter bit onone side thereof had a cumulative afi'ect on the cutting or groovingoperation, for on a cutting stroke the sharp edge of the bit would cutdeeper than the dull edge thus causing the cutter carrying tool to swingover from a predetermined course of travel to effect a slanting cut.Thereafter, on a return stroke the bit was forced against the side ofthe groove with greater pressure to further dull the cutting edge of thebit which in turn caused the tool to bear ofl. further on the followingcutting stroke to thereby increase the slant of the cut.

The present invention avoids the disadvantages of the prior art byproviding a tool having a plurality of cutter bits mounted in tandemthereon. Each cutter bit machines a narrower groove than the succeedingcutter bit and a means is provided which automatically retracts the lastcutter bit upon completion of a work stroke so as to permit the tool toclear the work on a return stroke. When this means is actuated toretract the last cutter bit, the first and last cutter bits are raisedto a position corresponding to the portions of the groove cut by thesecond and last cutter bits respectively, thus the tool is returnedthrough the groove without contacting the sides thereof. Upon completionof the return stroke the tool is lowered thereby positioning the cuttersfor a work stroke and means are simultaneously actuated to expand thelast cutters to a cutting position.

With the foregoing in mind it is an object of this invention to providea cutting and slotting tool in which the cutter bits are prevented fromengaging a workpiece on v the return stroke of the tool.

Another object is the provision of a tool for accurately slotting aworkpiece in a single operation.

Still another object is the provision of a tool for slot- States Patent0 ting a workpiece to any desired depth which will not wedge in the slotor steer to one side.

A further object is the provision of a tool for making wide finishingcuts on surfaces without chattering or gouging into the work.

Still another object is the provision of an adjustable tool for cuttinggrooves of various widths.

Yet another object is to provide a tool for accurately machining deepslots in a workpiece.

Another object is the provision of an adjustable tool which will permita machine to be operated at maximum speed on a return stroke.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 is a side perspective view from below of a cutting tool embodyingthe invention installed on a planer;

Fig. 2 is an enlarged side elevation of the cutting head of the toolshowing the position of the parts during a forward cutting stroke;

' Fig. 3 is an enlarged horizontal view from above taken along a linesubstantially corresponding to line 3-3 of Fig. 2 and showing a bitspreading wedge in the forward or cutting position;

Fig. 4 is a change position view similar to Fig. 3 but wherein the wedgeis shown partially withdrawn to retract the cutter bits so that theyclear the work on the return stroke; 7

Fig. 5 is a front view of the cutting tool taken from a pointsubstantially corresponding to line 5-5 of Fig. 2 showing the positionsof the, cutter bits during a cutting stroke;

Fig. 6' is a change position view similar to Fig; 5 in showing theretracted positions of the cutter bits during a return stroke;

Fig. 7 is a rear perspective view of the forward cutter bit;

Fig. 8 is a front perspective view of the central cutter bit disclosingthe knife edge which aids in clearing chips from the groove;

Fig. 9 is an exploded rear view of the after cutter bits and the holdertherefor; and

Fig. 10 is an enlarged perspective view of the wedge which spreads theafter cutter bits.

Referring now to the drawings wherein like reference numerals designatelike parts throughout the several views and more particularly to Figs. 1and 2 wherein there is disclosed a planer or similar machine 20 having avertically adjustable. tool head 21 with a clapper box 22 mountedthereon upon which is attached, in any well known manner, a slotting andgrooving cutter tool 23. The tool 23, which comprises the presentinvention; includes a base plate 24 on which is firmly secured achatter-free goosenecked tool holding blade 25 having a provision at itslower end for mounting a plurality of cutter bits 26, 27; and 28.

The central cutter bit 26, which projects lowest, is mounted in anaperture in the underside of the blade 25 and is held in position bymeans of a set screw 29 and, as shown in detail in Fig. 8, has a sharpleading edge 30 which breaks up chips and shavings cut from theworkpiece and prevents them from bunching between the central. cutterbit and the leading cutter bit 27 and thereby interfering with theoperation of the device.

The leading cutter bit 27, having a configuration best illustrated inFig. 7, is mounted in a cutout portion on the lower leading edge ofblade 25 and held rigidly in place by means of a bolt or other similarmeans 31 and a key (Fig. 7) which fits within a mating keyway (not 3shown) in the blade. The leading cutter bit 27 has a cutting edge thatis wider than that of the central or first cutter bit 26 and is locatedat a point higher than that of the first cutter bit so that it does notbegin to operate on a workpiece until after the first bit has cut acentral groove.

The third or after cutter bits 28 are a pair of side cutters mounted ona bifurcated bit holder 35 shown in Fig. 9 and which is rigidly securedat its upper forward part to the back of the blade by means of a key 36and bolts 37, 38, and 39. The holder has its lower end bifurcated toprovide spaced bit carrying members or legs 40, each of which is slottedat 41, to receive a cutter bit 28, each of which is securely fastenedtherein by means of a bolt 42. The bifurcated legs 40, each carrying acutter bit 23, are spread so as to separate the bits and cause them toengage the workpiece by means of a wedge shaped cam 45 which is movedrelative to the bit holder 35 to engage cammed surfaces 46 on the legsand thus cause the legs to move outwardly against the natural resiliencyof said legs.

The lateral movement of the after cutter bit 28 is eifeeted through amotion of the clapper box 22 relative to the machine 20 at the beginningand the end of a work stroke. The relative movement between the clapperbox 22 and the machine is transmitted to the cutter bits 28 through alinkage system which includes an adjustable link arm 50 having one endthereof pivotally mounted on the machine tool head 21 and the other endpivotally secured to the rearwardly extending arm of a wedge camcarrying bcllcrank 51 which is pivoted as shown to the upper portion ofthe tool holder 35 and carries the wedge cam on the depending armthereof. At the end of a work stroke the clapper box 22 pivots upwardlywhich causes the bcllcrank 51 to rotate counterclockwise to the positionshown by dotted lines in Fig. 2 to partially withdraw the wedge cam 45from between the bifurcated legs 40 and the resultant movement of thebifurcated legs moves the cutter bits 28 inwardly due to the resiliencyof the legs. The clapper box 22 remains in a raised position until thework has returned to the start position, whereupon it swings downwardlythereby rotating the bcllcrank 51 clockwise and causing the wedge cam 45to move the legs 40 outwardly along with the cutter bits 28 mountedthereon.

The width of the cut made by the after cutter bits 28 may be varied byadjusting the length of link arm through a threaded connection 52 toextend or shorten the arm and thus regulate the depth to which the wedge45 is inserted between the cutter carrying members 40 and therebydetermine the extent of the lateral movement of the cutter bits 28 andthe width of groove or slot to be out.

A cutter bit lubricating and cooling system 55 is provided which may beof the free flowing gravity type as shown in Fig. l. The system 55includes a lubricant-coolant container 56 having a liquid conductingtube 57 extending from a flow control petcock 58 attached to the bottomof the container and leading to a position from which thelubricant-coolant may be directed upon the leading cutter bit 27. If itshould be desired to use the tool 23 for cutting or grooving the side ofa workpiece then it may be expedient to modify the gravity flow system55 to include a compressed air supply (not shown) to force thelubricant-coolant from the container and also blow the chips produced bythe action of the leading cutter 27 from before the cutter.

Preparatory to operation, the tool 23 is mounted on the clapper box 22,and the finishing after cutter bits 28 are adjusted to a predeterminedcutting width by turning the adjusting threaded connection 52 whichshortens and lengthens the link arm 50 thereby causing the wedge 45 tomove between the cutter bit carrying legs 40 and thus cause the cutterbits to move transverse to the direction of the work stroke. A workpiece60 is then positioned on a bed plate 61 of the machine 20 and the tool23 is aligned with the workpiece so that the cutting edges of thefinishing after cutter bits 28 are equidistant from the center line of aproposed groove. Tool 23 is then lowered until the lead cutter bit 27 isat a predetermined distance above the workpiece 60 and the centralcutter bit 26 adjusted to a position where it contacts the upper surfaceof the work and there locked in place by means of the set screw 29.Petcock 58 is opened to permit the flow of lubricant-coolant upon thelead cutter 27 and the machine 20 is then actuated to begin operations.

In operation the tool 23 moves relative to the workpiece 66 to cut agroove having a configuration best illustrated in Figs. 5 and 6. On theinitial cutting or groov ing stroke the central cutter bit 26 alonecontacts the workpiece 60 to cut a slot along the center line of theproposed groove and on subsequent work strokes the tool 23 isautomatically fed downwardly a predetermined distance equal to or lessthan the depth of the slot cut by the central bit, then as each of thecutter bits 26, 27, and 28 is successively brought into contact with thework 60 it increases the width of the slot or groove cut by thepreceding cutter or cutters.

Upon the conclusion of each cutting stroke, the clapper box 22 ispivoted upwardly and outwardly thus causing the cutter bits 26 and 27 tobe raised to a position whereby on a return stroke they will passthrough the grooves cut by cutter bits 27 and 28 respectively and thewedge 45 is partially withdrawn from between the legs 40 by the actionof link arm 50 and bcllcrank 51 which causes the cutter bits 28 to beretracted or withdrawn inwardly and thus permit the cutter bits toreturn through the slot or groove without contacting the sides thereof,as shown in Fig. 6. The retraction of the cutter bits 23 and the raisingof cutter bits 26 and 27, so that they pass through the grooves cut bycutter bits 27 and 28, respectively, permits the work to be rapidlyreturned to the starting point without the danger of the cutter bitscontacting the side walls of the groove and thus prevents thepossibility of damaging the workpiece or the cutting edges of the cutterbits.

Upon return of the work to its starting position the clapper box 22 isautomatically pivoted downwardly thus causing the wedge 45 to move thecutter bits 28 outwardly and the tool 23 is lowered a predetermined distance to position the cutter bits 26, 27, and 28 for a subsequent workstroke.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. In a slotting mechanism for operating upon a workpiece with alternatecutting and return strokes, a bifurcated laterally resilient cutterholder, a plurality of cutters mounted on the holder, means to move thecutters outwardly upon the start of a cutting stroke to engage in aworkpiece, means to adjust the extent of the outward movement of saidcutters, and means independent of the workpiece to move the cuttersinwardly upon the start of a return stroke whereby said cutters passfree of the workpiece during the entire return stroke.

2. A slotting and grooving tool for machining deep slots in a workpiececomprising a bifurcated cutter holder, a pair of cutters mounted on theholder, a bcllcrank pivotally mounted on said holder, a wedge cammounted on the bcllcrank, and means to actuate said bcllcrank to movethe wedge cam between the cutters to cause the cutters to move outwardlyinto engagement with the workpiece.

3. A slotting and grooving tool for effecting deep slots in a workpiececomprising a bifurcated tool holder formed of resilient material, a pairof diametrically opposed cutters mounted on the tool holder, a wedge camfor separating the bifurcations of said holder, a wedge cam supportingmeans pivotally mounted on the holder, and means operable upon the startof a workstroke to actuate said supporting means to cause the wedge camto separate the bifurcations, whereby said cutters are moved intoengagement with the workpiece, said actuating means again operable uponthe termination of the means to vary the extent of the lateral movementof said cutters.

5. A slotting and grooving tool for machining slots in a workpiececomprising a bifurcated cutter holder, each portion of the holder formedby the bifurcation having a slot therein, a pair of diametricallyopposed cutter bits each mounted in one of the slots, a wedge cam forspreading apart the cutter carrying portions of said holder, a wedge camsupporting means pivotally mounted on the holder, means to actuate thesupporting means to cause the wedge cam to move between thecutter-carrying portions of the holder and move the cutters intoengagement with the workpiece, and means to vary the extent of travel ofthe cutters.

6. A slotting tool for machining deep slots in a workpiece comprising acutter holder having a pair of resilient cutter carrying legs, each ofsaid legs having a slot formed therein, a pair of diametrically opposedcutters mounted in said slots, a bellcrank pivotally mounted on theholder, a wedge cam secured on said bellcrank, means operable upon thestart of a work stroke to cause the wedge cam to move between said legsand move the cutters outwardly into engagement with the workpiece, andmeans to vary the extent of movement of said cutters, said actuatingmeans again operable upon the conclusion of the work stroke to withdrawthe wedged cam and thereby allow the legs to move the cutters inwardlywhereby the cutters may. move relative to the workpiece and return to awork stroke start position without contacting the machined portions ofsaid workpiece.

7. In a slotting mechanism, a depending blade having a first cuttermounted thereon, a second cutter mounted on the blade forward of thefirst cutter, a bifurcated tool holder secured on the after portion ofsaid blade and having a pair of third cutters mounted thereon, means forseparating the bifurcated portions of said holder to move the thirdcutters laterally of a work stroke, means for actuating said separatingmeans to extend the third cutters and to lower the blade upon the startof the work stroke, said first, second and third cutters each formingslots of greater width in a workpiece than the preceding cutters, saidactuating means raising the blade at the end of a cutting stroke to liftthe first and second cutters into slots formed by the second and thirdcutters respectively and causing the retraction of the third cutters soas to permit the first, second and third cutters to clear the workpieceon a return stroke. 1

8. In a slotting mechanism, a depending blade having a first cuttermounted thereon, a second cutter mounted on the blade forward of thefirst cutter, a bifurcated tool holder secured on the after portion ofsaid blade, a pair of diametrically opposed third cutters mounted onsaid holder, a bellcrank pivotally mounted on said holder, 21 wedge cammounted on the bellcrank, means for lowering the blade and actuating thebellcrank to engage the wedge cam and cutter holder to move the thirdcutters laterally of a work stroke to engage the workpiece upon thestart of said work stroke, said first, second and third cutters eachforming slots of greater width in the workpiece than the precedingcutters, said actuating means raising the blade at the end of a cuttingstroke to lift the first and second cutters into slots formed by thesecond and third cutters respectively and causing the retraction of thethird cutters so as to permit the first, second and third cutters toclear the workpiece on a return stroke.

9. A parting and slotting tool for machining operations wherein the toolmakes repeated passes over a workpiece to form therein a deep slot withfinished side walls, said tool having a main cutting edge to form agroove in the workpiece as the tool is moved through its cutting stroke,laterally extendible cutting edges disposed on the tool to the rearofthe main cutting edge to sequentially finish the side walls of thegroove formed by said main cutting edge, and means for retracting thelaterally extendible cutting edges from engagement with the groove sidewalls upon return movement of the tool.

10. The method of providing a deep groove in a planar surface with amachining tool comprising removing a strip from the surface to form agroove therein, relieving the walls of the groove to a depth less thanthe depth of the groove, and raising the tool on its return strokewhereby it may be passed through the relieved portion of the groove inreturning to a new cutting position.

References Cited in the file of this patent UNITED STATES PATENTS409,451 Caldwell Aug. 20, 1889 508,982 Rolston Nov. 21, 1893 828,425Ruedy Aug. 14, 1906 927,450 Chemack July 6, 1909 1,025,152 Mitts May 7,1912 1,327,410 Simeone Jan. 6, 1920 1,419,448 Davis June 13, 19222,275,327 Sheridan Mar. 3, 1942

